Study of Moderately Reinforced Concrete Beams Strengthened by Bolted-Side Steel Plates

Abstract

The strengthening technique which attaches steel plates to the side faces of existing reinforced concrete (RC) beams using anchor bolts has received worldwide acceptance in the past several decades. The performance of this type of beam, i.e. the bolted side-plated (BSP) beam, is mainly controlled by the degree of partial interaction at the steel-concrete interface. This partial interaction is a result of the longitudinal and transverse slips. This paper introduces an experimental study on the behavior of slips and shear force transfer in the BSP beams. A total of seven moderately reinforced BSP beams with different steel plate depths and bolt spacing were tested under four-point bending. Their behaviors were compared to the available test results for lightly reinforced BSP beams obtained by other researchers. Then a nonlinear finite element model was also developed to predict the behavior of BSP beams. The numerical simulation was also verified by the results of the experimental study successfully. The results show that moderately reinforced RC beams can be effectively enhanced in flexural strength and ductility by using deep steel plates. It was also found that the longitudinal and transverse slips were controlled by both the stiffness ratios of the steel plates to the RC beam and the force-slip response of the anchor bolts. This study enhances the basic understanding of behavior of BSP beams and the internal shear-transfer mechanism between the steel plates and the RC beam.